One of my alters can hear very slight changes in a person's voice. She can tell if they're speaking quicker, breathing different, clipping words, etc. in situations where an average person would not notice a difference. For me, this was her saving grace, and a type of hypervigilance, so she could tell when people were getting upset so she could hide, dissociate, or whatever she needed to do to stay safe.
It sounds like you either cut out or rely less on other senses, and your sense of sight is much stronger. Having hightened senses is parts of trauma response (hypervigilance) and could explain this type of dissociation. With most people who have dissociative disorders of one kind or another, it is usually a response meant to keep them as safe as possible, originally. Over time it becomes a common reaction, even when other responses might be healthier or work better. So it might be with you that paying attention to visual differences kept you safe at one point and has now become a common response to a trigger for you.
Hopefully some of that made sense.
xoxo
IJ